BRAINCAKEPlasma Membrane
Revision notes for Plasma Membrane in OCR Biology A (H020). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Membrane StructureAll living cells are enclosed by a plasma membrane which is made of a phospholipid bilayer.
- Fluid Mosaic ModelThe arrangement of the components of the plasma membrane is known as the fluid mosaic model.
- Membrane ProteinsMany proteins are embedded in the phospholipid bilayer.
- GlycoproteinsGlycoproteins are proteins attached covalently to carbohydrate chains.
- GlycolipidsGlycolipids are made from phospholipids covalently bonded to a carbohydrate chain.
- Extrinsic ProteinsExtrinsic proteins are also known as peripheral membrane proteins They are embedded in either the inner or outer layer of the phospholipid membrane.
- CholesterolCholesterol is a hydrophobic molecule that occurs within the membrane.
- Sites of Chemical ReactionsProteins embedded in the membranes of organelles such as chloroplasts and mitochondria are involved in chemical reactions.
- Effect of TemperatureThe phospholipids in the membrane are constantly moving laterally and are stabilised by cholesterol within the membrane.
- SolventsWater is a polar solvent.
- DiffusionDiffusion is the net movement of molecules or ions from a region of high concentration to a region of low concentration until evenly distributed.
- Diffusion Across MembranesSome particles are able to pass through the phospholipid bilayer.
- Facilitated DiffusionLike simple diffusion, facilitated diffusion is a passive process.
- Active TransportActive Transport is the movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration…
- Bulk TransportBulk transport is a form of active transport and requires energy.
- OsmosisOsmosis is the passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a…
- Osmosis in Animal CellsAnimal cells are enclosed in a cell membrane made of a phospholipid bilayer.
- Osmosis in Plant CellsPlant cells contain various solutes in the cytoplasm.